Low-viscosity solutions of alkaline-earth metal alkoxides in aprotic solvents, method for the production of same and use for the production of Ziegler-Natta catalysts

ABSTRACT

One or more concentrated low-viscosity solutions of alkaline earth alkoxide compounds M(OCH 2 R 6 ) 2-a-b (OR 7 ) a [O(CHR 8 ) n OR 9 ] b  in mixture with a metal alkyl compound M(R 10 R 11 ) in an aprotic solvent and related methods are disclosed herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage entry of International PatentApplication PCT/EP2015/068513, filed on Aug. 12, 2015, which claimspriority from German Patent Application No. 10 2014 215 919.9, filedAug. 12, 2014, German Patent Application No. 10 2014 216 067.7, filedAug. 13, 2014, and German Patent Application No. 10 2014 224 139.1,filed Nov. 26, 2014. Each patent application identified above isincorporated here by reference in its entirety.

Magnesium alkoxides are needed for synthesis of supported olefinpolymerization catalysts of the Ziegler-Natta type, among other things.To do so, according to the publication EP 1031580, insoluble alkoxides,such as magnesium ethoxide, are used in the form of spherical particles,which are converted to the active form by reaction with titaniumchloride or some other compound (e.g., Cp₂TiCl₂) having titanium-halogenbonds:Mg(OEt)₂+Cp₂TiCl₂→Mg(OEt)_(2-x)Cl_(x)+Cp₂TiCl_(2-x)(OEt)_(x)(x=0 to 2)

The publication WO 85/02176 describes another possibility for synthesisof supported Ziegler-Natta catalysts starting from soluble magnesiumalkoxides. Whereas most magnesium alcoholates, such as the magnesiumsalts of methanol, ethanol, propanol, isopropanol, tert-butanol, etc.,are insoluble in aprotic solvents, many Mg compounds of primary alcoholshaving a branch in position 2 have proven to be soluble in hydrocarbons.It is known from the publication WO 85/02176 that the magnesium salts of2-methyl-1-pentanol or of 2-ethyl-1-hexanol in concentrations of 1.3mol/L, for example, will dissolve in cyclohexane. Mixed Mg alkoxides,i.e., those with two different alkoxide radicals Mg(OR¹)_(n)(OR²)_(2-n),may be soluble in hydrocarbons if the corresponding alcohol R′OH is aprimary alcohol with branching in position 2, and the correspondingalcohol R²OH is a secondary alcohol, for example.

One disadvantage of hydrocarbon solutions which do not have any otherdissolved metal except for magnesium is their relatively high viscosity.In addition, it is impossible to prepare such solutions directly byreacting magnesium metal with the alcohol in the desired hydrocarbonwithout adding any additives, which cause problems. To permit a directreaction at all, the magnesium metal must be activated, which can beachieved by etching with iodine. With this measure, the reaction rate isstill very low, even when using highly reactive Mg powder. Thus, thedocument EP 0156512 describes the preparation of a dilute solution ofmagnesium bis(2-ethylhexoxide) in dodecane by using iodine. A 10-hourreaction time is necessary at a reaction temperature of 145° C., and theproduct is obtained in the form of a viscous solution. Therefore, toavoid extremely long reaction times, magnesium alcoholate solutions ingeneral are therefore prepared by starting with commercially availabledialkyl magnesium compounds (R₂Mg). However, this synthesis route hasthe disadvantage that a relatively expensive magnesium source (namelythe R₂Mg compounds whose synthesis requires haloalkanes) is used. Inaddition, it implies a stipulation of certain solvents, namely saturatedhydrocarbons. Dialkyl magnesium compounds, for example, dibutylmagnesium, butylethyl magnesium and butyloctyl magnesium are availablecommercially only in saturated hydrocarbons such as hexane or heptane.

Furthermore, saturated hydrocarbons (R³H and R⁴H, for example, butane oroctane) are unavoidably formed in alcoholysis according to the equation:R³R⁴Mg+2ROH→Mg(OR)₂+R³H+R⁴H

It is therefore impossible to synthesize magnesium alcoholates in purelyaromatic solvents, such as toluene or ethylbenzene, starting fromcommercially available dialkyl magnesium compounds.

Another synthesis variant for producing soluble alkaline earthalcoholates consists of re-alcoholization of insoluble alkaline earthalcoholates synthesized from readily volatile alcohols (for example,ethanol) with a higher boiling alcohol, for example:Mg(OR⁵)₂+2ROH→Mg(OR)₂+2R⁵OH

One disadvantage is the relatively high, cost-intensive effort involvedin this method because the alcoholate Mg(OR⁵)₂ must first be synthesizedfrom the volatile alcohol R⁵OH and magnesium metal and isolated, thenreacted with a less volatile alcohol, for example, 2-ethylhexanol, andthen the more volatile alcohol R⁵OH must be removed by distillation, forexample.

The relatively high viscosity of magnesium alkoxide solutions is causedby association phenomena. It is known from the document U.S. Pat. No.6,734,134 that the viscosity can be reduced by adding alkyl aluminumcompounds. The preferred ratio between the alkyl aluminum compound andMg alcoholate is between 0.001:1 and 1:1, more preferably between 0.01and 0.1:1 and most especially preferably between 0.03 and 0.05:1.

Finally, it is known from the document WO 2010/146122 that mixedalkaline earth alkoxide compounds M(OCH₂R⁶)_(2-x)(OR⁷)_(x) can beproduced in mixture with an aluminum compound Al(OCH₂R⁶)_(3-y)(OR⁷)_(y)in aprotic solvents, starting from an alkaline earth metal and twodifferent alcohols, wherein

-   -   M is an alkaline earth metal selected from Mg, Ca, Ba, Sr;    -   OCH₂R⁶ is an alkoxide radical consisting of at least 3 carbon        atoms and at most 40 carbon atoms with a branch in position 2        relative to the O function, i.e., R⁶=—CHR⁸R⁹ where R⁸, R⁹        independently of one another denote C₁-C₁₈ alkyl radicals;    -   R⁷ is an alkyl radical with 2-15 carbon atoms, which is either        linear or has a branch at ≥position 3 (relative to the O        function);    -   and the sum of x plus y gives a number between 0.01 and 0.8,        preferably between 0.02 and 0.3 and especially preferably        between 0.03 and 0.2.

The product solutions prepared with the help of this method haverelatively high concentrations of alkaline earth alkoxide compounds(i.e., c_(Mg)>0.5 mol/kg), but in the case of products with relativelylow concentrations of viscosity-reducing Al compounds (≤3 mol %, basedon the dissolved alkaline earth metal concentration) are stillunsatisfactorily high, typically with ≥1000 cP at room temperature (RT).According to the document U.S. Pat. No. 6,734,134 a low Al concentrationis crucial for use as a Ziegler-Natta catalyst support materialaccording to the document U.S. Pat. No. 6,734,134.

Furthermore, dialkyl magnesium compounds such as butylethyl magnesium ordibutyl magnesium can be used directly for synthesis of Ziegler-Nattacatalyst support materials (chemically MgCl₂). However, one disadvantageof the use of dialkyl magnesium compounds is their relatively highproduction cost and the fact that hydrocarbon solutions of such metalorganyls are pyrophoric. These pyrophoric properties require the use ofspecial shipping, storage and handling regulations which are adisadvantage.

Mixtures of dialkoxy magnesium and dialkyl magnesium compounds are alsoknown. Thus Example XVIII of U.S. Pat. No. 4,634,786 describes thesynthesis of a heptane-cyclohexane solution containing a 1:1 complexconsisting of magnesium 2-methyl-1-pentoxide and dibutyl magnesium.However, exact stoichiometric amounts of dialkyl magnesium compound andalcohols are used in the other example of the aforementioned patent, sothat Mg(OR¹R²) compounds having an exact stoichiometric composition(i.e., those that are free of excess R₂Mg) are formed. One can find inExamples I, II, III references to the fact that it is favorable from thestandpoint of viscosity to use an excess of alcohol. Thus, for example,the viscosity of the product solution having a stoichiometriccomposition is “perceptibly” reduced by adding approx. 5 mol %2-methyl-1-pentanol in Example 1.

The invention has taken as its object to find concentrated alkalineearth metal oxide compounds in aprotic solvents, in particularhydrocarbons that have a low Al concentration (e.g., <5 mol % based onthe Mg content), which have a low viscosity (e.g., <500 cP at RT) at thesame time and are not pyrophoric and also to provide methods for theirsynthesis.

This object is achieved by making available mixtures of alkaline earthalkoxide compounds M(OCH₂R⁶)_(2-a-b)(OR⁷)_(a)[O(CHR⁸)_(n)OR⁹]_(b) and ametal alkyl compound M(R¹⁰R¹¹) with an alkaline earth metalconcentration in the range of 0.2 to 1.8 mmol/g in aprotic solvents,wherein

-   -   M is an alkaline earth metal selected from Mg, Ca, Ba, Sr;    -   OCH₂R⁶ is an alkoxide radical consisting of at least 3 and at        most 40 carbon atoms with a branch in position 2 relative to the        O function, i.e., R⁶=—CHR¹²R¹³ with R¹², R¹³ denoting        independently of one another alkyl radicals C₁-C₁₈;    -   R⁷ is an alkyl radical with 2-15 carbon atoms which is either        linear or has a branch in ≥position 3 (relative to the O        function)    -   R⁸ is an alkyl radical with 1 to 6 carbon atoms, which is either        linear or has a branch at ≥position 3 (relative to the O        function)    -   R⁹ is an alkyl radical with 2-15 carbon atoms which is either        linear or has a branch    -   R¹⁰ and R¹¹ are any alkyl radicals with 1-15 carbon atoms    -   n is an integer from 1 to 4    -   a+b≤2 wherein a and b may assume values of 0 to 2 and    -   the molar ratio M(OCH₂R⁶)_(2-a-b)(OR⁷)_(a)[O(CHR⁸)_(n)OR⁹]_(b)        to M(R¹⁰R¹¹) is from 99.5:0.5 to 60:40, preferably from 99:1 to        70:30 and especially preferably from 95:5 to 80:20.

It has surprisingly been found that by adding even small amounts ofalkaline earth metal alkyls to solutions of alkaline earth alkoxidecompounds in aprotic solvents, their viscosity can be reduceddrastically. This is in contrast with the technical teaching known fromU.S. Pat. No. 4,634,786 that only the addition of further alcohol tomagnesium alkoxide solutions having a stoichiometric composition has aviscosity-reducing effect.

The solutions according to the invention contain from 0.1 to 30 mol %,preferably 1 to 20 mol % and especially preferably 3-15 mol % activebase R₂Mg, determined by direct titration with sec-butanol andbiquinoline as an indicator and based on the total amount of alkalineearth metal M in solution.

In addition, an aluminum compoundAl(OCH₂R⁶)_(3-c-d)(OR⁷)_(c)[O(CHR⁸)_(n)OR⁹]_(d) is preferably containedin the solutions according to the invention, wherein

-   -   OCH₂R⁶ is an alkoxide radical consisting of at least 3 and at        most 40 carbon atoms with a branch in position 2 relative to the        O function, i.e., R⁶=—CHR¹²R¹³ where R¹², R¹³=independently of        one another alkyl radicals C₁-C₁₈;    -   R⁷ is an alkyl radical with 2-15 carbon atoms which is either        linear or has a branch at ≥position 3 (relative to the O        function);    -   R⁸ is an alkyl radical with 1 to 6 carbon atoms which is either        linear or has a branch at ≥position 3 (relative to the O        function);    -   R⁹ is an alkyl radical with 2-15 carbon atoms which is either        linear or has a branch    -   n=an integer from 1 to 4,        c+d≤3 and both c and d may assume values of 0 to 3 and wherein        the amount of aluminum compound        Al(OCH₂R⁶)_(3-c-d)(OR⁷)_(c)[O(CHR⁸)_(n)OR⁹]_(d) based on the        dissolved alkaline earth metal is in the range of 0 to approx.        20 mol %, preferably 0.2 to 5 mol %, especially preferably 0.5        to 4 mol %.

The aprotic solvent is or contains either one or more aliphaticcompounds with 5 to 20 carbon atoms, wherein both cyclic and open chaincompounds are possible. Preferred compounds include cyclohexane, methylcyclohexane, hexane, heptane, octane, nonane, decane, dodecane, decalinas well as commercial boiling cuts (gasoline fractions).

The aprotic solvent may additionally contain or consist of aromatics.Preferred aromatics include benzene, toluene, ethylbenzene, xylenes andcumene.

In another embodiment of the invention, the alkaline earth alkoxidesolution according to the invention still contains polar aproticsolvents such as ether or tertiary amines.

The alcohol (HOCH₂R⁶) which is branched in position 2 is especiallypreferably selected from the group consisting of isobutanol,2-methyl-1-pentanol, 2-ethyl-1-butanol, 2-ethyl-1-pentanol,2-ethyl-4-methyl-1-pentanol, 2-propyl-1-heptanol, 2-methyl-1-hexanol,2-ethylhexanol and 2-ethyl-5-methyl-1-octanol or any mixture of at leasttwo of the alcohols listed. The primary alcohol (HOW) is preferablyselected from the group consisting of ethanol, propanol, butanol,pentanol, hexanol, octanol, decanol, dodecanol, 3-methylbutan-1-ol orany mixture of at least two of the alcohols listed. The alcoholHO(CHR⁸)_(n)OR⁹ which contains an alkoxy function is preferably a C₂-C₄glycol monoethers, for example, 2-ethoxyethanol, 3-ethoxy-1-propanol,3-ethoxy-1-butanol, 2-(2-ethylhexoxy)ethanol, 2-butoxyethanol,2-hexyloxyethanol as well as 1,3-propylene glycol monobutyl ether or anymixture of at least two of the alcohols listed.

The products according to the invention can be synthesized, for example,according to two different methods.

The first method begins with commercial alkaline earth metal, preferablymagnesium metal which is preferably in the form of a powder, granules orshavings. The metal is placed in an anhydrous aprotic solvent,preferably aromatic or aliphatic hydrocarbons, in an inertized stirredcontainer, dried and provided with a protective gas (nitrogen or argon).Then an alkyl aluminum compound, e.g., trialkyl aluminum such astriethyl aluminum, tributyl aluminum, an alkyl aluminum hydride, such asdibutyl aluminum hydride, an alkyl aluminum halide, such as dibutylaluminum chloride or an alkoxyaluminum compound, such as diethylaluminum ethoxide may be added. In general the molar ratio of alkylaluminum compound to the alcohols is from 0 to 0.1:1, preferably from0.005 to 0.04:1. The aluminum compound may also be added entirely orpartially after the alcohol or to the alcohol(s).

Then the desired alcohols, i.e., the alcohol HO(CHR⁸)_(n)OR⁹ and/or abranched alcohol HOCH₂R⁶ and/or an unbranched primary alcohol with 2-15carbon atoms (HOR⁷) or one having a branch at ≥position 3 is/are addedeither as a mixture or one after the other. Preferably the primaryalcohol R⁷OH is added first, then the alcohols selected from the othersubstance groups are added. This addition may take place at temperaturesbetween 0 and 180° C., preferably between approx. 40 and 140° C. Theaddition most especially preferably takes place at the boiling point ofthe solvent being used, i.e., in the case of toluene, for example, atapprox. 110° C. The reaction time depends on the reactivity of thealkaline earth metal that is used, in particular that of magnesium aswell as the acidity of the alcohol used, the stoichiometric ratiobetween the alkaline earth metal, in particular magnesium, and thealcohols as well as the reaction temperature. If the alkaline earthmetal in particular the magnesium is used in excess (preferably 1 to 300mol %, especially preferably from 10 to 100 mol %), then a reaction timeof 1 to 6 hours is sufficient in the reflux procedure. The reaction ispreferably continued until practically all the alcohol has reacted,i.e., its concentration is <0.01 mmol/g, preferably <0.001 mmol/g.

After the end of the reaction, which can be recognized by the subsidenceof the hydrogen stream, the solution of an alkaline earth metal alkylcompound, e.g., MgR¹⁰R¹¹ is added to the relatively viscous reactionmixture. Another brief increase in viscosity is usually observed, but itis reversed to the opposite after adding a few mol % MgR¹⁰R¹¹, i.e., theviscosity of the reaction solution surprisingly changes to a lowviscosity rather suddenly; depending on the alcohols used as well asother parameters, this effect occurs after adding 1-20 mol % metal alkylcompound.

However, further addition of MgR¹⁰R¹¹ causes only a minor furtherdecline in viscosity, which is insignificant in terms of handlingtechnology. For example, if an approx. 30 wt % heptane solution ofmagnesium bis(2-ethylhexoxide) containing barely 3 mol % Al is mixedwith 9 or 4 mol % of a dialkyl magnesium compound, for example,butylethyl magnesium, then the viscosity drops from ≥1000 cP to approx.50 or 100 cP at RT.

The second preferred preparation method starts with solutions of dialkylmagnesium compounds in aprotic solvents. The desired alcohol(s) is/areadded to these solutions in a stoichiometric amount leading to theproducts according to the invention. The substances may be added in anyorder. A prefabricated alcohol mixture may also be used. It is alsopossible to start with the alcohol or alcohols preferably in mixturewith aprotic solvent and then add the dialkyl magnesium component.Finally, a simultaneous dosing in the solvent supplied is alsoconceivable.

The products produced by the method according to the inventionsurprisingly have a very low viscosity, despite the high alkaline earthmetal concentration of ≥0.5 mol/kg, preferably ≥1.0 mol/kg. The alkalineearth metal concentrations are preferably in the range of approx. 0.4 to1.6 mmol/g, especially preferably from 0.7 to 1.4 mmol/g. Theviscosities measured at room temperature are generally less than 300 cP,preferably less than 200 cP, especially preferably less than 100 cP atMg concentrations ≥1 mmol/g and ≤1.5 mmol/g.

The dissolved aluminum content is in the range of 0 to approx. 20 mol %,preferably in the range of 0.2 to 15 mol %, especially preferably in therange of 0.5 to 4 mol %, based on the dissolved alkaline earth metal.

The products according to the invention are used to producepolymerization catalysts, in particular heterogenized polyolefincatalysts of the Ziegler-Natty type. Furthermore, they may be used asbases, for example, in organic synthesis.

EXAMPLES

All the reactions were carried out in dry glass equipment inertized withargon. Commercial magnesium shavings were used. The concentrations of Mgand Al were measured by means of ICP (inductively-coupled plasma).

The active base is determined by direct titration with 1M 2-butanolsolution in hexane against 2,2-biguinoline as the indicator. Colorchange from red to gray.

Example 1 Preparation of a 35% Solution of Magnesiumbis(2-ethylhexoxide) in Mixture with 6 Mol % bibutyl Magnesium inHeptane

Using a 0.5 L double-jacketed glass reactor with a reflux condenser anda dropping funnel, 32.0 g magnesium shavings and 352 g heptane wereplaced as starting materials. Then 11.3 g of a 20 wt % solution oftriethyl aluminum in heptane, 1.8 g ethanol and 171.9 g 2-ethylhexanolwere added and heated to the boiling point, then refluxed for 4 hours,whereupon 14.6 L gas was formed and a viscous solution of magnesiumbis(2-ethylhexoxide) was obtained. A sample was taken and its viscositywas determined (1025 cP at 25° C.).

The reaction mixture was then cooled to approx. 80° C. and 54.6 g of adibutyl magnesium solution in hexane (Mg=1.08 mmol/g) was added. Afterthis addition, the resulting solution had a low viscosity and was easyto handle. The light gray suspension was syphoned off and filtered,yielding 579 g of a non-viscous liquid with a magnesium content of 1.22mmol/g. The product solution in turn contained 0.030 mmol/g aluminum andhad an active base content of 0.15 mmol/g (corresponding to 0.075 mmol/gBu₂Mg, approx. 6 mol %).

Yield: 98% of the theoretical

Viscosity (Brookfield, 25° C.): 33 cP

In the UN test N.2, N.3, the product solution was found to benon-pyrophoric.

Example 2 Preparation of a 29% Magnesium Decanolate Solution in Hexanein Mixture with 14 Mol % Dibutyl Magnesium

Using a 0.5 liter double-jacketed glass reactor with a reflux condenserand dropping funnel, 82.0 g of a dibutyl magnesium solution in hexane(Mg=1.11 mmol/g, 91 mmol) was added as the starting mixture. Then 23.6 gn-decanol (149 mmol) was added while stirring vigorously. A gelatinousreaction product was formed temporarily at the addition point, but itcompletely dissolved as stirring was continued. After the end of dosing,a non-viscous colorless and clear solution was obtained.

Yield: 104 g solution

Total magnesium content: 0.88 mmol/g

Active base unit: 0.24 mmol/g

Viscosity (Brookfield, 25° C.): 4.8 cP

In the UN test N.2, N.3, the product solution was found to benon-pyrophoric.

Comparative Example 1 Preparation of an Approx. 30% Magnesium DecanolateSolution in Hexane

Using a 0.5 liter double-jacketed glass reactor with a reflux condenserand dropping funnel, 85.0 g of a dibutyl magnesium solution in hexane(Mg=1.11 mmol/g, 94 mmol) was added. Then 31.2 g n-decanol (197 mmol)was added while stirring vigorously. After adding approx. 90% of thetotal amount of alcohol, the gelatinous phase formed at the additionpoint would always dissolve more slowly and then would no longerdissolve at all. After the end of dosing, a stiff gel was formed andcould not be liquefied even by heating (approx. 80° C.).

No sample could be taken by syringe due to the gelatinous consistency.

Example 3 Preparation of a 35% Solution of Magnesiumbis(2-ethylhexoxide)/Magnesium Decanolate (75:25) in Mixture withApprox. 5 Mol % butylethyl Magnesium in Heptane

Using a 0.5 liter double-jacketed glass reactor with a reflux condenserand a dropping funnel, 32.0 g magnesium shavings and 352 g heptane wereplaced as starting materials. Then 11.3 g of a 20 wt % solution oftriethyl aluminum in heptane, 1.8 g ethanol and a mixture of 128.9 g2-ethylhexanol and 52.2 g 1-decanol were added and heated to the boilingpoint. Refluxing was continued for 3.5 hours, whereupon 16.0 L gas hadformed and the viscous solution of the mixed magnesium alkoxide wasobtained. A sample was taken and its viscosity was determined (3800 cPat 25° C.).

The solution was cooled to 100° C. and 55.1 g of a butylethyl magnesiumsolution in heptane (Mg=1.09 mmol/g) was added. After the addition, alow viscosity solution that could be handled easily was obtained. Thelight gray suspension was syphoned and filtered, and 534 g of anon-viscous liquid with a magnesium content of 1.19 mmol/g was isolated.The product solution still contained 0.033 mmol/g aluminum and had anactive base content of 0.11 mmol/g (corresponding to 0.055 mmol/gBuMgEt, 4.6 mol %).

Yield: 88% of theoretical

Viscosity (Brookfield, 25° C.): 16 cP

In the UN test N.2, N.3, the product solution was found to benon-pyrophoric.

Example 4 Preparation of a 34% Solution of Magnesium bis(2-ethylhexoxidein Mixture with 5 mol % butylethyl Magnesium in Toluene

Using a 0.5 liter double-jacketed glass reactor with a reflux condenserand a dropping funnel, 32.0 g magnesium shavings and 352 g toluene wereplaced as starting materials. The 9.0 g of a 25 wt % solution oftriethyl aluminum in toluene, 1.8 g ethanol and 171.9 g 2-ethylhexanolwere added and the mixture was heated to the boiling point. Refluxingwas continued for just 4 hours, whereupon 16.4 L gas had formed and aviscous solution of the magnesium alkoxide was obtained.

Then the mixture was cooled to 100° C. and 56.5 g of a dibutyl magnesiumsolution in heptane (Mg=1.08 mmol/g) was added. After this addition, alow viscosity solution that could be handled easily was obtained. Thelight gray suspension was syphoned off and filtered, and 576 g of anon-viscous liquid with a magnesium content of 1.21 mmol/g was isolated.The product solution again contained 0.030 mmol/g aluminum and had anactive base content of 0.13 mmol/g (corresponding to 0.065 mmol/gBuMgEt, 5.4 mol %).

Yield: 97% of the theoretical

Viscosity (Brookfield, 25° C.): 94 cP

In the UN test N.2, N.3, the product solution was found to benon-pyrophoric.

Comparative Example 1 and a comparison of the viscosity data before andafter addition of dialkyl magnesium solution in Examples 1 and 3 showthe positive effect achieved by adding dialkyl magnesium solution tomagnesium alkoxide solutions (Examples 1 and 3) and/or using asubstoichiometric amount of alcohol in the reaction with dialkylmagnesium solution (Example 2 and Comparative Example 1).

Whereas all the product solution prepared according to the inventionwith Mg concentrations between 0.88 and 1.22 mmol/g and Alconcentrations of ≤3 mol % could be handled very well and had a lowviscosity (viscosity at 25° C.<100 cP), the product solutions containingdialkyl magnesium were extremely viscous: the viscosities of the liquidproducts were between >1000 cP and 3800 cP. If no alcohol branched inposition 2 (HOCH₂R⁶ consisting of at least 3 carbon atoms and at most 40carbon atoms with a branch in position 2 relative to the O function,i.e., R⁶=—CHR¹²R¹³ where R¹², R¹³=independently of one another alkylradicals C₁-C₁₈) is used but instead only unbranched alcohols are used,the result of a complete reaction and/or use of a slight excess ofalcohol (Comparative Example 1) is a gelatinous product that is notcomparable or transferable in any other way. However, in the presence ofapprox. 14 mol % dibutyl magnesium, a watery, low-viscosity product isobtained. Such a product cannot be produced according to U.S. Pat. No.4,634,786 because, according to this prior art document, “(a) aliphatic2-alkyl-substituted primary monoalcohols; or (b) mixtures of theaforementioned (a) alcohols with C₃-C₁₂ aliphatic secondary or tertiaryalcohols; or (c) mixtures of said (a) alcohols with C₁-C₁₂ aliphaticprimary linear unsubstituted alcohols; wherein the molecular ratios ofsaid (a) alcohols to said (b) alcohols and of said (a) alcohols to said(c) alcohols (amounts to) 1 for said (a) alcohols to 0.1 to 2 of said(b) alcohols and said (c) alcohols,” i.e., in each case, (a) alcoholsbranched in position 2 are needed.

All the product solutions according to the invention are non-pyrophoric.

The invention claimed is:
 1. A solution of alkaline earth alkoxidecompounds M(OCH₂R⁶)_(2-a-b)(OR⁷)_(a)[O(CHR)_(n)OR⁹]_(b) in mixture withan alkaline earth metal alkyl compound M(R¹⁰R¹¹) with an alkaline earthmetal concentration in the range of 0.2 to 1.8 mmol/g in an aproticsolvent, wherein M is an alkaline earth metal selected from the groupconsisting of Mg, Ca, Ba, and Sr; OCH₂R⁶ is an alkoxide radicalconsisting of at least 3 and at most 40 carbon atoms with a branch inposition 2 relative to the O function; R⁷ is an alkyl radical with 2-15carbon atoms, which is either linear or has a branch in ≥position 3relative to the O function; R⁸ is an alkyl radical with 1 to 6 carbonatoms, which is either linear or has a branch at ≥position 3 (relativeto the O function; R⁹ is an alkyl radical with 2 to 15 carbon atoms,which is either linear or has a branch; R¹⁰ and R¹¹ are any alkylradicals with 1 to 15 carbon atoms; n is an integer from 1 to 4; a+b≤2wherein a and b each have a value of 0 to 2; and the solution has amolar ratio of M(OCH₂R⁶)_(2-a-b)(OR⁷)_(a)[O(CHR⁸)_(n)OR⁹]_(b) toM(R¹⁰R¹¹) that is in the range of from 99.5:0.5 to 60:40.
 2. Thesolution according to claim 1, characterized in that the alkaline earthmetal concentration is in the range of 0.4 to 1.6 mmol/g.
 3. Thesolution according to claim 1, characterized in that the solution, atthe alkaline earth metal concentration of ≥1 mmol/g to ≤1.6 mmol/g, hasa viscosity, measured at room temperature, of ≤300 cP.
 4. The solutionaccording to claim 1, characterized in that the molar ratio ofM(OCH₂R)_(2-a-b)(OR⁷)_(n)[O(CHR⁸)_(n)OR⁹]_(b) to M(R¹⁰R¹¹) is in therange of from 99:1 to 70:30.
 5. The solution according to claim 1,characterized in that it contains from 0.1 to 30 mol % M(R¹⁰R¹¹),determined by direct titration with sec-butanol and biquinoline as theindicator and based on the total alkaline earth metal M in solution andthe solution non-pyrophoric according to one selected from the groupconsisting of United Nations test N.2, United Nations test N.3, and bothUnited Nations test N.2 and United Nations test N.3.
 6. The solutionaccording to claim 1, characterized in that the alkaline earth metalconcentration is in the range of 0.7 to 1.4 mmol/g.
 7. The solutionaccording to claim 1, characterized in that the solution, at thealkaline earth metal concentration of >1 mmol/g to <1.6 mmol/g, has aviscosity, measured at room temperature, of <100 cP.
 8. The solutionaccording to claim 1, characterized in that the molar ratio ofM(OCH₂R⁶)_(2-a-b)(OR⁷)_(a)[O(CHR⁸)_(n)OR⁹]_(b) to M(R¹⁰R¹¹) is in therange of from 95:5 to 80:20.
 9. A method for synthesis of alkaline earthalkoxide compounds M(OCH₂R⁶)_(2-a-b)(OR⁷)_(a)[O(CHR⁸)_(n)OR⁹]_(b) inmixture with a metal alkyl compound M(R¹⁰R¹¹) according to claim 1, themethod comprising: mixing a solution of the metal alkyl compoundM(R¹⁰R¹¹) in an aprotic solvent with one or more alcohols selected fromthe group of HOCH₂R⁶, HOR⁷, HO(CHR⁸)_(n)OR⁹, and any mixture thereof,wherein half of the molar ratio of the total number of moles of allalcohols to the metal alkyl compound is from 99.5:0.5 to 60:40.